DFT study on gas-phase hydrodeoxygenation of guaiacol by various reaction schemes

<p>Guaiacol is an important phenolic component present in pyrolytic bio-oils; and in this work its hydrodeoxygenation (HDO) by various reaction schemes has been considered within the framework of density functional theory. In this computational study, primarily three reaction schemes for the HDO of guaiacol are considered. In the first reaction scheme (<b>RS 1</b>), guaiacol undergoes hydrogenolysis at O–CH₃ bond site of methoxy group to produce catechol and methane followed by HDO of catechol forming phenol and water, followed by HDO of phenol producing benzene and water and finally benzene leading to cyclohexane formation. In the second reaction scheme (<b>RS 2</b>), guaiacol undergoes hydrogenolysis at C_aromatic–O bond of methoxy group producing phenol and methanol followed by hydrotreatment of phenol to form cyclohexane along with same intermediates as in the first reaction scheme. In the third reaction scheme (<b>RS 3</b>), HDO of guaiacol compound at C_aromatic–OH sigma bond produces anisole and water; and then anisole follows two secondary pathways to produce cyclohexane. In this computational study, the transition state optimisations, vibrational frequency and IRC calculations are carried out by B3LYP functional with 6-311+g(d,p) basis set using Gaussian 09 and Gauss View 5 software package.</p

Electronic Supplementary Material for the manuscript entitled "Platinum Catalyzed Hydrodeoxygenation of Guaiacol in Illumination of Cresol Production: A DFT Study". from Platinum catalyzed hydrodeoxygenation of guaiacol in illumination of cresol production: a DFT study

Arrhenius equations and optimized molecular structures of all elementary reaction steps

Quantum chemical study on gas phase decomposition of ferulic acid

<p>Ferulic acid, representing phenolic fraction of bio-oil, is considered to be a model compound in this study for its decomposition into various end products such as ethylbenzene, eugenol, <i>cis</i>-isoeugenol, vanillin, 4-ethylguaiacol, guaiacol, and acetovanillone using density functional theory approach. Results of bond dissociation energies indicate that cleavage of methyl group from ferulic acid is the lowest energy-demanding bond scission amongst all 14 bond cleavages. Primary end product by decomposition of ferulic acid is found to be ethylbenzene and its production occurs through the formation of intermediate products such as 4-hydroxycinnamic acid, cinnamic acid and styrene. Demethoxylation of ferulic acid gives rise to the production of 4-hydroxycinnamic acid which further undergoes the formation of cinnamic acid by dehydroxylation reaction route. The formation of cinnamic acid in this study is carried out using three reaction schemes 1–3 and its further reduction to ethylbenzene is performed using two reaction possibilities. Finally, favourable pathway is found to be decarboxylation of cinnamic acid to produce vinylbenzene followed by the production of ethylbenzene using hydrogenation of C=C chain double bond. Furthermore, thermochemistry of each reaction scheme is performed at atmospheric pressure and at a wide range of temperature of 598–898 K.</p